Carnegie Mellon researchers advance toward inexpensive 3-D printed organs

Coronary artery structure being 3-D bioprinted--Courtesy of Carnegie Mellon University

Reseachers at Carnegie Mellon have hacked a sub-$3K consumer 3-D printer to create biological-material models of embryonic hearts, arteries, bones and even human brain tissue. The hope is that this work could lead to tissue creation that is adequate to repair soft tissue in the human body. The work is being done using open-source software, enabling other researchers to more easily replicate it.

Other researchers have already used 3-D printed implants in humans for applications including the production of implants of bone plates to repair large cranial defects and bioresorbable tracheal splints. But soft structures, of the kind that would be useful to repair tissues, haven't been as much of an early focus.

"We've been able to take MRI images of coronary arteries and 3-D images of embryonic hearts and 3-D bioprint them with unprecedented resolution and quality out of very soft materials like collagens, alginates and fibrins," said Adam Feinberg, an associate professor of Materials Science and Engineering and Biomedical Engineering at Carnegie Mellon University, in a statement. He leads the Regenerative Biomaterials and Therapeutics Group there and headed this study, which was published in the Oct. 23 issue of the journal Science Advances.

Ultimately, the researchers expect that they can create soft hydrogel scaffolds for tissue engineering applications. It said its fabrication to create a wide range of 3-D structures based on 3-D imaging with spatial resolution and fidelity was able to "match or exceed" prior efforts.

The researchers adapted a MakerBot Replicator, which retails for $2,899, with a custom syringe-based extruder for hydrogels. The material is extruded from the syringe into a support bath, where it gels into a filament. The group also employed open-source software.

"The challenge with soft materials--think about something like Jello that we eat--is that they collapse under their own weight when 3-D printed in air," explained Feinberg. "So we developed a method of printing these soft materials inside a support bath material. Essentially, we print one gel inside of another gel, which allows us to accurately position the soft material as it's being printed, layer by layer."

The technique is known as Freeform Reversible Embedding of Suspended Hydrogels, or FRESH. In the next iteration, researchers expect to incorporate real heart cells into these 3-D printed tissue structures--offering them a scaffold to form contractile muscle.

"Not only is the cost low, but by using open-source software, we have access to fine-tune the print parameters, optimize what we're doing and maximize the quality of what we're printing," Feinberg said. "It has really enabled us to accelerate development of new materials and innovate in this space. And we are also contributing back by releasing our 3-D printer designs under an open-source license."

- here is the announcement
- and here are the full study results